The invention relates to a device for connecting structural components, with a base part, which is disposed at the one structural component, a spacer, which is in threaded engagement with the base part and is supported with one end at the other structural component, and a connecting screw, which is inserted frictionally engaged through the spacer.
A known device of this type is described in EP-B-0 176 663 and is used to connect two structural components, which are disposed at a particular distance from one another, with the help of the connecting screw without distorting the structural components as the connecting screw is tightened. The connecting screw is inserted, for example, through the structural component, which is to be supported at the spacer, and is then screwed into an internal thread of the other structural component, which is connected with the base part. During this screwing-in motion, the spacer is taken along by friction. The thread between the spacer and the base part is a left-handed thread, so that the spacer is screwed further out of the base part and approaches the structural component, which is held by the head of the connecting screw, until this component finally lies in contact with the front surface of the spacer.
However, if the distance between the structural components, which are to be connected, is greater than the maximum adjusting path of the spacer, it may happen that, as the connecting screw is screwed in, the spacer is screwed completely out of the base part. Since the spacer in this case is accessible only with difficulty, if at all, it is difficult to restore the threaded engagement between the spacer and the base part.
In the state of the connecting device as delivered, the spacer normally is screwed completely into the base part. From practice, a connecting device is known, for which the spacer in this position is in contact with a stop and, in addition is held in position by a spring-mounted latch. However, it must be possible to overcome the resistance of the latch when the connecting screw is being screwed in. Accordingly, it is not impossible that, because of improper handling or jarring, the spacer, before use of the connecting device, becomes detached completely from the base part, so that the parts of the connecting device fall apart and are lost.
For stability reasons, the base part and the spacer should consist of metal. In that case, however, the danger exists that the structural components, which are to be connected to one another, are scratched during the assembly by the spacer, which protrudes from the base part. This problem occurs, for example, in vehicle construction, when a cross member is to be fastened with the help of two such connecting devices between two body parts of the vehicle, which have already been painted.
It is therefore an object of the invention, to provide a device of the type mentioned above, with which damage by the spacer to one of the structural parts, which is to be connected, is avoided.
Pursuant to the invention, this objective is accomplished owing to the fact that the spacer is surrounded by a jacket of a softer material, preferably of plastic, and that the jacket, at least in the state, in which the spacer and the base part together have the smallest axial dimension, is flush with the front surface of the spacer or of the harder core of the latter or protrudes relative to this front surface.
Advantageous developments of the invention arise from the dependent claims.
A possible embodiment is characterized in that the spacer has a jacket, which overlaps the base part and in that stops are disposed at this jacket and at the base part, which limit the unscrewing movement of the base part and the spacer. In that case, the protective jacket is part of the spacer.
In the case of a different embodiment, the jacket is seated on the base part. Since the device, in the original state, before the start of the assembly work, is adjusted to the smallest possible axial dimension, the spacer lies protected in the jacket until the structural components, which are to be connected, are brought into position and the connecting screw is screwed in.